Fukushima's toxic water pool grows as Tepco dithers

By Yuriy Humber

31 August 2013 — 3:00am

The Tokyo Electric Power Company is trying to decide what to do with the largest pool of radioactive water in the history of nuclear accidents. It can either dump it in the ocean, let it evaporate into the air, or both.

The more than 330,000 tonnes of water with varying levels of toxicity is stored in pits, basements and hundreds of tanks at the wrecked Fukushima nuclear plant.

Leaks: Nuclear regulators inspect the storage tanks.Credit:Reuters

The government said this week it would take a bigger role in trying to staunch the toxic outflow that has grown to 40 times the volume accumulated in the atomic disaster at Three Mile Island in the US.

Processing and disposing of the water - enough to fill a large crude oil tanker or 132 Olympic-size swimming pools - is presenting one of the most challenging engineering tasks of our generation, former nuclear engineer Michael Friedlander said.

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Tokyo Electric (Tepco) has chopped down forests for space to add more water tanks to the site 220 kilometres north-east of Tokyo. The steel storage tanks are vulnerable to spills due to earthquakes as well as leaks, representing ''a very clear and present danger to the plant site and to the people working there'', said Mr Friedlander, who spent 13 years on US nuclear plants.

''There are really only a few ways you can get rid of it. You put it in the ocean or it's going to have to be evaporated,'' he said. ''It's a political hot spot, but at some point you cannot just continue collecting this water.''

Deciding on a disposal method is increasingly urgent after a series of leaks, including one last week which Japan's safety regulator described as the most ''severe incident'' since the site was disabled by the 2011 earthquake and tsunami.

Tepco, the power company, has 300 tonnes of water flowing into the reactors each day for cooling, while another 400 tonnes of groundwater is seeping from hills behind the plant into basements and mixing with contaminated run-off.

Tepco is then pumping hundreds of tonnes out of the basements each day to storage tanks where it awaits treatment to extract cesium and strontium via two filter systems.

After sufficient processing, the water is classified as low-level contaminant for disposal.

Tepco said this week that the second of the two filter systems failed this month and it will not be repaired until next month. A leak of at least 300 tonnes from one of the 1000 tonne storage tanks last week prompted the Nuclear Regulation Authority to warn that more may be prone to similar spills. The watchdog also criticised Tepco for management of the tanks.

''This is rapidly becoming an international issue, so I think there is some pressure from countries in the region, including China, Korea and others,'' the founder of Tokyo-based energy consultant Mathyos, Tom O'Sullivan, said.

Japan's nuclear industry used the tank storage method even before the Fukushima accident and it has long been shown to be unsafe, a professor in the nuclear engineering department at the University of California, Berkeley, Joonhong Ahn, said. ''The process towards solution is not simple,'' yet someone in charge must make the decision to release water with a low level of contamination, he said. ''The remedies taken by Tepco have been very incomplete and took too long.''

Tepco has yet to decide how to dispose of the contaminated water, spokeswoman Mayumi Yoshida said. But before it can act it will need approval from the government, residents and fishermen, who are already suspicious of the company's motives.